Method for cutting glass



Nov.- 17, 194 2.

J. H. BOICEY ETAL METHOD FOR CUTTING GLASS Fil ed June 27, 1940 2Sheets-Sheet l Ennentor: UHME'J H. 50/667 (OBEKTE LECK.

attorney Nov. 17,1942. J. H. BOICEY ET AL 2,302,174

METHOD FOR CUTT-ING GLASS If //P Inventor:

014/455 H. 50/0 2")! #0050 a 56K.

attorney Patented Nov. 17, 1942 UNITED STATES PATENT OFFICE METHOD FORCUTTING GLASS James H. Boicey and Robert F. Leek, Toledo, Ohio,assignors to Libbey-Owens-Ford Glass Company, Toledo, Ohio, acorporation of Ohio Application June 27, 1940, Serial No. 342,759

2 Claims.

The present invention relates to an improved method for cutting disksfrom glass sheets or Plates and particularly from laminated safetyglass.

Laminated safety glass ordinarily comprises two sheets or lights ofglass bonded to one another by'an interposed layer of plastic materialto form a composite structure. In the cutting of laminated safety glass.it has been customary to first score one of the glass sheets and crackthe same along said score line by flexing the laminated sheet with thehands or by the use of pliers, after which the second glass sheet isscored along a line directly opposite the first score line and saidsecond sheet then cracked.

along its score line. The glass is then separated along the lines of outby stretching the plastic interlayer, and the plastic finally severed byuse of a razor blade or the like.

This invention contemplates the cutting out of disks from laminatedsafety glass by the general method referred to above but furtherembodies the provision of a novel method of and apparatus for flexingthe glass sheets after scoring to effect the cracking thereof along thelines of cut whereby such operation may be accomplished in a more rapid,accurate and economical manner.

Among other objects of the invention is the provision of a method forflexing the glass sheets along the lines of cut whereby the edges on thecut disks will be smoother and more perpendicular to the plane of theglass; whereby better superimposition of the two pieces of glass formingthe disk is obtained; and whereby less flaking of the glass along thelines of cut is caused by the flexing thereof so that fewer chipsresult.

Other objects and advantages of the invention will become more apparentduring the course of the following description, when taken in connectionwith the accompanying drawings.

In the drawings, wherein like numerals are employed to designate likeparts throughout the same:

Fig. 1 is a side elevation of apparatus provided by the invention forscoring the glass sheets;

Fig. 2 is a similar.view of the apparatus for flexing the glass sheetsafter scoring to efiect the cracking thereof along the score lines;

Fig. 3 is a sectional view of a portion of a sheet of laminated safetyglass, one sheet of which has been scored;

Fig. 4 is a sectional view illustrating the cracking of the glass sheetalong the score line;

Fig. 5 is a viewsimilar to Fig. 3 but showin one sheet of glass crackedalong its score line and the other sheet scored and ready for cracking;

Fig. 6 is a view similar to Fig. 4 illustrating the cracking of thesecond sheet of glass;

Fi '1 is a plan view illustrating the means for accurately positioningthe scored sheets of glass upon the flexing apparatus; and

Fig. 8 is a side elevation of a modified form of apparatus which may beemployed either in the scoring of the glass sheets or the flexinthereof. v

with reference now to the drawings, the apparatus illustratedin Fig. 1for scoring the glass sheets and the apparatus illustrated in Fig. 2 forflexing said sheets to cause cracking thereof along the score lines aresubstantially the same, except for the particular tools used to performthe respective operations upon the glass. The cutting apparatus isdesignated in its entirety by the letter A and comprises a horizontalbase III (hereinafter termed the cutting table) for supporting the sheetof laminated safety glass II to be cut. As shown, the sheet of laminatedsafety glass l I comprises the two sheets or lights of glass l2 and i3and an interposed layer of plastic material H bonded together to form aunitary structure. Secured to the cutting table It is a verticalstandard l5 carrying the superimposed horizontal arms l6 and I1 providedat their outer ends with vertically aligned bearings l8 and I9respectively within which is rotatably mounted a vertical shaft 20. Theshaft 20 is provided adjacent its lower end with a transverse openingthrough which is inserted a horizontal rod 2i having a bearing portion22 at its outer end for receiving the ferrule 23 carrying at its lowerend the rotatable steel cutting wheel 24. The cutting ferrule 23 issecured within bearing 22 by a set screw 25, while horizontal rod 2| issecured to shaft 20 by a set screw 26.

The scoring of the glass sheet, supported upon cutting table It, isaccomplished by downward pressure upon shaft 20 and rotation thereofthrough a complete circle to cause the steel cutting wheel 24 to bemoved over and in engagement with the glass in a circular pattern. Thesize of pattern to be out can be varied by adjusting the rod 2|horizontally relative to shaft 20 to give the desired radius. Theturning of the shaft 20 may be manually effected by means of anoperating handle 21 secured to the upper end thereof. The shaft 20 isalso normally urged upwardly to maintain the cutting wheel 24 out ofcontact with the glass by means of a compression spring 28 encirclingsaid shaft and bearing at its opposite ends against bearin I8 and theinner end of operating handle 21.

The flexing apparatus is designated in its entirety by the letter B and,as stated above, is of substantially the same construction as cuttingapparatus A; the only difference being that the.

rotatable steel cutting wheel 24 of the latter is replaced by a freelyrotatable ball bearing 29 mounted within a recess 30 in the lower end offerrule 23a. For the sake of simplicity, those parts of the flexingapparatus B which are similar to correspondingparts of cutting apparatus"A are designated by the same reference numerals primed by the letter a.

In carrying out the invention, the 'sheet of laminated glass l l to becut'is placed horizontally upon the cutting table III of cuttingapparatus A and the upper glass sheet l2 thereof scored by turning thehandle 21 and simultaneously urging th cutting wheel 24 downwardly intoengagement with the glass. Upon turning of the han- 4 die 21, thecutting wheel 21 will effect the scoring of the top surface of the glasssheet I! in a circular pattern. as indicated at if in Fig. 3.

The sheet of laminated glass H is then transferred from the cuttingapparatus A to the flexpath of 360 degrees and at the same time forceddownwardly to urge the ball bearing 28 into engagement with the glass.This results in the application of pressure to the glass sheet I! progressively and continuously along a path directly opposite the line ofout 8| causing running of the cut 3| in glass sheet I! and the crackingof such sheet along said line.

The sheet of laminated glass H is then removed from the flexing tableIlla and returned to the cutting table II where the second sheet ofglass It is scored along a line of out directly above and in alignmentwith the score line H in glass sheet II as indicated at 32 in Fig. 5.Following this scoring operation, the laminated sheet is again returned,in reverse position, to the flexing apparatus B where pressure isapplied to the sheet of glass I! along the score line 3| thereof asshown in Fig. 6 causing running of the cut' in the glass sheet I! alongthe score line 32 Just applied to the glass whereby to effect thecracking of said sheet along said score line. After the two sheets ofglass i2 and I3 have been scored and cracked in the above manner, thecut disk may be removed in any desired manner. For instance, suitableentering cuts may be made in the glass sheets and the glass separatedaround the score lines 3| and 32 to permit severing or breaking of theplastic interlayer H.

To facilitate the accurate positioning of the scored laminated sheet Ifupon the flexing table Illa, there is preferably carried by said table asuitable template SI of paper or the like having marked thereon acircular pattern corresponding to the circular score line and with whichsaid score line is adapted tobe aligned. Thus, as shown in Fig. '7, thetemplate 33 has applied thereto a circular pattern 34 of the same sizeas 75 the disk to be cut and positioned directly beneath the path oftravel of the ball bearing 28. The numeral 35 designates a glass sheet,either plain or laminated, scored along the circular line 38, and inpositioning the sheet it is placed upon the flexing table in such a.manner that the score line 38 will align or register with the circularpattern 35 applied to template 33. This assures that the ball hearing I!will engage the upper surface of the glass sheet directly above thescore line 86.

likewise, in cutting laminated safety glass and especially when scoringthe second sheet of glass,

it is essential that such score line he in alignout in the first sheetcan be lined up with the circular pattern applied to the template,thereby assuring that the two lines of cut will be directly opposite oneanother.

We have found by actual use that disks can be cut from sheets oflaminated safety glass by the above method and apparatus in a rapid,accurate and economical manner. Further, that smoother edges can beobtained on the circular pieces of glass as well as bettersuperimposition of the two pieces of glass constituting the lamination.It has likewise been observed that less flaking of the glass along thescore lines results when the glass is flexed in this manner wherebyminimum chipping of the edges is obtained. Althoughin some cases it maybe necessary to perform some edge work on the edges of the cut disks, ithas been found that due to the better cutting of the circles resultingfrom the use of our method and apparatus considerably less edge work isrequired.

It has been found practical to score a large number of circles on onesheet of glass at the same time and to then transfer the laminated sheetto the flexing apparatus where the glass can be cracked along all of thecut circles. After all of the circular cuts in theone sheet of glasshave been obtained the laminated sheet may be returned to the scoringapparatus and the process repeated. While it is preferred to use a ballbearing 29 as the pressure element for flexing the glass sheets becauseof its rolling and substantially point contact with the glass, othertypes of pressure elements, either stationary or movable, may be used ifdesired.

If desired, instead of operating the scoring and flexing devices A and Bby hand, they could be power actuated. For instance, instead of applyingdownward pressure to the handle 21 or 210 by hand, an air piston couldbe associated with the upper end of the respective shaft 20 or 200. asshown in Fig. 8. In such figure, the outer end of arm- I isprovided'with a cylinder J1 within which is mounted a piston 38 carriedat the upper end of a piston rod 3!, said piston rod passing downwardlythrough the bottom of cylinder I1 and provided at its lower end with acircumferential flange ll. The upper end of the shaft 28 or 20s is alsoprovided with a circumferential flange ll and interposed between saidflanges 40 and ll are ball bearings I! which permit rotation of shaft 2|or 28a relative to piston rod 39. A pipe 43 leading to the upper end ofcylinder 31 is adapted to supply the compressed air thereto. The shaftor 20a is also positively driven by means of 'a sprocket chain 44 1 thesprocket 45 may be provided with a key slidod and apparatus has-beentound-ipractical for and claims, is to be given a broadinterpretation to include not only circularpieces but piecesot trainedabout a sprocket 45 carried by said shaft glass which are non-circularor approximately and driven from suitable source of power. In. circular.Obviously, it is not essential to the order to permit rotation of theshaft 20 or 20a carrying out of the method above described thatsimultaneous with vertical movement thereof, the cutting apparatus andflexing apparatus be I ,of the same construction.

able within a vertical key-way 46in said shaft. j It is to be understoodthat the form of the The shaft 20 or 20a is normally urged upwardly,invention herewith shown and described is to be .by means of acompression spring' -fl, to maintain taken as the preferred embodimentof the same,,

the cuttlng tool or flexing-element out of enand that various changes inthe shape, size and 1gagementwlth-thecglass. 10, arrangement of partsmay be resorted to without We have foundthat lless pressure is-requireddeparting from thespirit of the invention or the tobririgabout'runningoffthe cutmsing the same scope of the subjoined claims.type'of g'lassandiaiipther conditionsbeinfg equal, We claim: when-asoftplastic ihterlayer -is employcdlthan wheniahard'plastic interlayerisused; Where-15 safetyglass including two sheets of glass and an hardplastic-interlayersiare employed less'pres *interposedlayerof plasticmaterial, comprising sure canfof course'be resortedto,bylheating the 1first "scoring one sheet of glass, then applying lamination tosoften"theplastic"inter1ayer the pressure =torth second glass sheetprogressively temperature of-ihe'atingf heih limitdfonlyf by; h etmiueasiymong a path opposed to the the'destruction oifth'estabilityofthelamin t j'lineto effect flexing ofthelaminated sheet orthe production iotdefects -therein, "napp es, and cracking of the firstglass sheet along said sure isl-alsoirequired in theeutting of laminated:scoreline-then-scoring ithesecond sheet of glass glass where theplasticfinterlayer' is thickerthanw, along a line opposed-t0 the firstscore line, and

where a thin layer is employed. 1 y "then-fapplyingpressure to theflrstsheet of glass Although the'invention has beenillustratedin 2 1progressively and continuously along; the line of the drawings andparticularly described here it cutthereof to flexthe laminated sheet andcause inabove in connection with the cuttingoutflof crackingyoi" thesecond-sheet of glass along its disks from laminated safety glass, thesame methscoreline, I g v "2. The method oi cuttingdisks i'rom laminatedscoring and running the cuts on ordinary sheets gd safety glassincluding two sheets of glass and of glass. In: such case, the singlesheet-oi glass 1 an interposed layer of plastic material, compriswouldbe "scored upon one side, by the scoring" ing. first scoringone sheet ofglass, then applying apparatus A, turned overxand transferred to the f,rollingpressure and substantially point contact flexing apparatus B, sothat the pressure ap- ,tothe second glass sheet progressively andconpliedj by the ball hearing would follow a path 35' tinuously along apath'opposecl to the score line 1 along the scored line but onthesurface of the v =to efiect flexing of the laminated sheet andcrackglass opposite tothat which had been scored, 7 ingofthe first glasssheet along said score line,

Likewise, while the invention has been dethen scoring thesecond sheet ofglass along a line scribed hereinabove in connection with the cutopposed to the first score line, and then applying tingordisksorcircular-pleces from glass sheets 40 rolling pressure andsubstantially point contact or plates, it will be apparent that themethod to the firstsheet of glass progressively and conmay alsob'egpracticedincutting, pieces ofglass. tinuouslyalong'the line ofcutthereoi to flex the s of other shapes irompthe sheetsior plates..Therelaminated sheet and cause cracking otthe second fore, the word dias used in thespecification' shcet'of glass along its score line. a

i JAMES H. BOICEY.

ROBERT I". LECK.

- 1.; The methodfof cutting disks from laminated

